S
M
T
W
T
F
S
26
98°
76°
27
99°
75°
28
99°
76°
29
98°
77°
30
99°
77°
31
99°
76°
1
98°
76°
2
98°
75°
3
98°
73°
4
98°
74°
5
99°
73°
6
98°
75°
7
100°
77°
8
102°
76°
9
100°
76°
10
100°
75°
11
99°
74°
12
100°
73°
13
95°
73°
14
95°
74°
15
97°
76°
16
97°
76°
17
99°
77°
18
99°
75°
19
98°
74°
20
98°
74°
21
99°
73°
22
99°
73°
23
98°
72°
24
98°
72°
25
97°
73°
26
95°
74°
27
96°
74°
28
93°
71°
29
93°
71°
30
94°
73°
31
94°
74°
1
95°
73°
2
93°
72°
3
92°
70°
4
92°
71°
5
95°
73°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in San Marcos
San Marcos's August 2026 forecast shows daily high temperatures ranging from 92° to 102°, with overnight lows between 70° and 77°. The average high for August is 97° with an average low of 74°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in San Marcos. See also: September | October | November.
